Modelling and experimental investigation of pore-like flaw-strength response in structural ceramics

Although important, fracture strength in structural ceramics remains difficult to predict due to the inherent micropores, and there is a tremendous need for more precise modelling of pore-like flaw-strength relationship. In this study, classical crack problems were successfully transformed into pore-like flaw-strength models by adding a reasonable stress correction factor proposed by Gomez. Based on the accurate fracture toughness measurement and the precise laser introduction of flaws vs strength tests, the optimized Sato-Takahashi model, which is suitable for any cross-sectional shapes and sharpness flaws, was found to have fairly good prediction for fracture strength in five typical structural ceramics. The experimental error at very small-sized flaws was analyzed from the aspects of the critical flaw size and the inherent flaw size detected by nano-CT. Overall, the simple and user-friendly optimized Sato-Takahashi model could pave the way for quantitative assessments of reliability and failure causes for fine ceramics.